This invention relates to the production of a heat-reflecting glass plate, and more particularly to a method of coating a glass plate surface with a heat-reflecting metal oxide film by spraying a solution of a thermally decomposable organic metal compound onto a heated glass surface to thereby cause thermal decomposition of the metal compound to metal oxide.
A popular method of producing a heat-reflecting glass plate is to coat one side of a glass plate with a heat-reflecting metal oxide film by spraying a solution containing a thermally decomposable organic metal compound dissolved in an organic solvent onto a heated glass surface to thereby cause thermal decomposition of the organic metal compound to metal oxide. Titanium oxide TiO.sub.2 is one of metal oxides known as suitable for this purpose, and the present invention is particularly concerned with the formation of a titanium oxide film, or a metal oxide film of which the principal component is titanium oxide, on a glass plate surface by the above-mentioned spraying method.
The above-mentioned spraying method is quite favorable for industrial production of a heat-reflecting glass plate. However, when a titanium oxide film is formed on a glass plate surface by this method, the titanium oxide film is liable to have a countless number of opaque spots each as small as 5 to 20 microns in diameter. The existence of such spots renders the titanium oxide film cloudy and, hence, significantly injures the appearance of the film. Moreover, the strength of adhesion of the titanium oxide film to the glass surface becomes weaker in the areas of the respective spots, so that the titanium oxide film having such spots becomes inferior to a uniform and defectless titanium oxide film also in durability and particularly resistance to chemical attacks.
This problem has already been recognized, and it has been tried to solve this problem by, for example, using a special solvent and/or a certain additive, but until now a fully effective measure has not yet been found.